Bus power supply for supplying the bus system with 15 V DC for up to 35 bus participants. The bus power supply is short-circuit proof. Two LEDs indicate the operating status, any short circuit, and activities on the bus. Input connection for mains voltage and output connection for bus line, polarity-reversible, for powering the end devices. Connections are made via screw terminals. Use of standard installation materials. Error feedback to the system is possible. Housing made of flame-retardant polycarbonate, halogen-free, suitable for installation in control cabinets on a 35 mm DIN rail according to EN 50022, protection class IP20, ambient temperature 0 to 50 °C.